Door closer and check



-Aug. 26,

Filed May '7, 1929 F C. RRSN DOOR CLOSER AND CHECK 2 Sheets-Sheet l ATTORNEY Aug 26, 1930 F. ci. GARRISQN ,773,9&

DOOR CLOSER AND CHECK Filed May '7, 1929 2 Sheets-Sheet 2 'a-mw ATTORN EY i Patented ujg. 1930 UNiTED STATE s PATENT oFFIcE FORREST C. GARRISONTOF EVANSTON, ILLINOIS, ASASIGNOR TO THE OSGi-AR C. RIXSON COMPANY, A CORPORATION 0F ILLINOIS DOOR CLOSER AND CHECK 1 Applicationy led May' 7, 1929. Serial No. 361,135.

The automatically acting mechanisms for closing and checking theclosing movement of doors and the like are commonly known as door checks. These mechanismsare most commonly of the fluid pressure type, that is, in the door-closing movement'of the relatively movable parts of the mechanism, a suitable fluid such as air lor oil is employed as a checking medium, by forcing it through a restricted passageway, a suitable valve being employed for adjusting the amount of such restriction, and a freely opening one-Way relief valve being provided to afford free dooropening relative movement of the'parts of the mechanism, such mechanism also commonly including a door-closing spring to which the checking action is opposed. lith this arrangement the door of course will be gradually closed at the rate of speed provided for by the adjustment of the checking device` and with a` force dependent upon the adjustment of the spring. y e

It is often *desirable to be able to close a door quickly, for various reasons. In many instances this is attempted in the case of doors equipped with door checks. In such case the speed of the closing movement of the` door can only be slightly accelerated or increased,

but the pressure upon the checking fiuid is abnormally increased, so that thereby a great strain is placed upon the checking mechanism as well as upon the hinges of the door with the likelihood of breaking some part of the mechanism or of tearing it loose, and similarly Wit-1 respect tothe hinges of the door.

An object of this invention is to eliminate thepossibility of the checking mechanism being-"broken in this yWay, as Well as also toprovide for-quickly or more speedily closing the door when desired Without liability of damage. Other objects of theinvention are dependability in operation,simplicity of construction, durability, and convenience and economy of manufacture. Other objects and advantages Will hereinafter appear.

According to the invention a yieldable re-.

lief device is provided which yields only under an abnormal or excessive strain applied to the door closing andchecking mechanism- 5 in the door-closing direction of movement of its relatively movable parts in their checking operation. This relief device becomesoperative torelieve the strain when the door-clos ing force exceeds that of the door-closing spring and provides such relief Within an ample margin of safety. In carrying out the invention vmeans are provided for relieving excessive pressure of the checking uid by providing a freer. How or less restricted passage thereof from fone side of achecking piston to the otherrin the checking movement of the piston in its cylinder'. I

Such pressure relief meansy comprisea. spring-pressed valve member the springof which is maintained'under a normal initial tension so that the spring will not yield un der normal conditions of checking movement of the piston, but Will yield only under abfl normal or excessive pressure, thereby to provide additional space for the passagefor liow of the checking liuid,-W'hile such pressure is still Within the limits of safety. More desirably, adjusting meansv are provided for this spring for varying its normal or initial tension in order that thereby .a more accail rate determination for aording relief vmay be obtained, aswell as accommodation to various conditions of use and dilferent installations. The invention further includes various features of construction and combinations of parts, as will appear fromv the following description. 4It is obvious that the invention may be carried out in-various Ways by means ofmore onless dierent or varying constructions. i

tion of a door closer and check 'embodying the l invention shown as installed at'l'the bottomy of adoor.

`Fig. 2 is a vvertical transverse section on the Fig. 3 is an enlarged partial section similar to Fig. 1', more particularly Ishowing the coma somewhat modified form of the construction appearing in-Figs. 1, 2 and 3;

Fig. 5 is a partial longitudinal vert-ical section similar to Fig. 1 but showing a somewhat modified embodiment of the invention as compared with that shown in Figs. 1, 2 and 3; y

Fig. 6 is a View similar to Fig. 5 but showing a modification in which the pressure relef valve device is carried by the piston, an

Fig. 7 is a view similar to Fig. 6 illustrating a variant form of construction as compared with that shown in Fig. 6.

In the accompanying drawings the inven tion is shown as embodied in a door' closer and' check mechanism which in other respects is of substantially a usual construction heretofore commonly employed. The door closer and check shown in the drawings is what is known as a single-acting door check, that is to say, it is designed for single-acting doors and adapted to be applied at the -bottom thereof. A door closer and check of sub.

stantially similar igeneral construction is disclosed in the patent to RiXson No. 1,064,255 of June 10, 1913, and is also shown in the RiXson catalogue No. 2, of the Oscar C. RiX- son Co., Chicago, Ill., issued January 1, 1926, on pages 46 and 47 thereof. However, it is to be understood as obvious that the present invention may as well be embodied in door closers and checks of which the operating mechanism is in general otherwise constructed, regardless of whether it is doubleacting or single-acting and similarly regard-` less of whether it is designed or adapted to be installed at the bottom or at the top of the door, that is, whether it may be a floor check or an overhead check. Also while the particular construction shown in the drawings is designed to utilize a suitable liquid as a checking fluid, the construction and manner of operation so far as the present invention is concerned would be substantially similar in the case of a door closer and check designed to employ air, for example, as the checking fluid.

The particular construction of the embodi ment of the invention shown in Figs. 1 to 3 inclusive of the drawings will now be described, and in this connection the parts of the operating mechanism which remain substantiallyl unchanged by the embodiment of the invention 'therein will be described first in order that the features of the invention may be more readily understood. A substan- 1 and a bottom closure 3 at its other end. Above this bottom closure 6 the top of the body part 1 is provided with an upwardly projecting neck. or tubular boss 4 forminga journal bearing. This casing box is set into the floor 5 and is shown as covered by a carpet strip or threshold 6 vthrough which the journal bearing 4 projects.,y This casing boX is shown as located adjacent to the door jamb 7 and adjacent to the hinge edge and forward or inner side of the door 8.

A crank shaft is journaled in and projects above the top of the bearing 4 and at its lower end is provided with a'step bearing in the bottom closure 3, including bearing balls 10. The lower end of the door 8 carries a door plate or leaf 11 the end of which adjaadjustably engages a cylindrical key pin 14 which is set into the crank shaft 9. Obviously, as the door 8 is swung inward it will rotate the crank shaft 9 in a clockwise direction as viewed from above in Fig. 1. The crank shaft 9 is provided with a crank comprising an eccentric or pin portion 15 which connects together upper and lower crank arms 16 and 17 on the crank shaft 9, it being understood from Fig. 1, as will presently more clearly appear, that this crank projects towards the inner or visible side of the doo:` 8, in the line of sich* with the axis of the crank shaft 9. Y v

A doornclosing spring shown asa vertically arranged coiled torsion spring 18 is mounted in the other end of the casing boiY with its upper end lanchored to a plate 19 carried by the cover plate-2 to beprotatively adjustable by means of a capstan 2O -for adjusting the resilient resistance or tension of the spring. The spring 18 surrounds a core 21 on which is pivoted a swinging plate or lever arm 22 to'which the lower end of the spring 18 is connected. On its lower side andrear edge (Fig. 1), this spring-connected swinging plate 22 Acarries a pivotscrew 23, while the. end of the lower crank arm 17 of the crank shaft 9 on its lower side carries a similar pivot screw 24, and these two pivot screws 23 and 24 are connected together by means of a pull member comprising pivotally jointed links as shown. .lt should now be evident that the spring 18 resists or opposes the opening of the door 8 and that when the door S is opened this spring will. be further tensioned or wound, whereupon when the door Sis re-y leased. such spring will become effective for closing the door. The closing of the door is controlled by the checking mechanism now to be described. y, f

A cylinder 26 is rigidly fixed in the body part 1 of the casingfboX, for example, by means of lateral iianges 27 on the cylinder box while the other end of the cylinder is resting upon shelves 28 in the casing-box and firmly .held in place by means ,of screws 29. Theend of this cylinder adjacent to the crank shaft 9 is shown as fully open'into the casing closed. A piston or plunger 30 in the cylinder 26 carries a vertically arranged pivotpln 31 on which lis pivoted the inner end of a connecting rod or pitman 32 the other or outer end of which-is pivoted on the crank or eccen- ,tric pin of the crank shaft 9. It should now be clear that opening movement of the door 8 will lwithdraw the piston l30 towards the open endofthe cylinder 26' while closing 5 movement of the door will move the piston 30 towards the closed end .of thecylinder 26. In the construction shown the hermetically jsealed casing box is to be filled or subst-antially vso with a suitable checking liquid, which advantageously also may be a lubricant for the moving parts of the mechanism.

The checkingj mechanism may be provided with usual means to permit, free opening movement of the door, 'which of course is against the resistance of the springvl8. In the construction shown, abore is provided through the piston A having `an'inner en-V larged portion 33 andan outer reduced portion 34 forming a valve seat-for a usual valve ball 35 loosely contained in the enlarged portion 33 of this bore and vprevented from escaping therefrom by means of a usual crosspinl 36, so that thereby thel valve ball 35 forms a freelymovable one-way escape valve which.

affords substantially free or unobstructed passage of the checking fluid through Ithe piston 30 in the outward or door-'opening movement of the latter,`while as the piston moves inward in its door-closingor checking movement, this valve 35 will be closed by the pressure ofthe checking uid to prevent the y voutward lpassage thereof .from the inner closed end of the'cylinder 26 through the piston 30.

. The door closer and check construction as so farjdescribed is substantially the-same as that heretofore employed ahd as disclosed in thetwo above mentioned prior publications. There yet remains to be described the feature by which the usual checking actionis' secured, that is, by which the inward or doorclosing movement of the checking piston 30 is checked by restricting the passage of the.

checking fluid around this piston, and also 55' the Feature, in accordance with this invention, by reason of which under excessive or abnormal pressure of the checking Huid in its checking action,- a less restrictedor larger opening or passageway is provided lfor this fluid around the piston, whlch prevents the accumulation of excesslve pressure 1n such i fluid and thus relieves thel` operating parts of the checking mechanism` from excessive strain, so as to safeguard them from breakage, while at the same time permittingl the door 8 to be closed much more quickly than otherwise. v In the particular embodiment 'of the invention now being described these two features are combined in a single construe.- tion which serves both of these functions, but in which'the normal checking action takes place in substantially the same way as heretofore in a usual construction.

` The wall of the cylinder 26, for example conveniently the side wall at the top, is thickened to, provide a longitudinal ridge or lug 37, intermediate of the-length of which a projection or boss 38 extends through the top wall of the casing body 1, against the inner side of which the lug 37 fits. AY rather large bore or socket 39, the outer portion of which is screw-threaded, extends down through the boss 38 and into the thickened wall portion 37 and-has a tapering or conical bottom Wall- 40 which is provided centrally with a reduced -aperture or bore 41 forming an 'inlet open ing.v A longitudinal bore 42 opens at one end into the lower end of the inlet aperture 41 and a short'vertical bore 43 opens into the other end of'this longitudinal-bore 42 and forms if t) an outlet from thec'ylinder 26 .adjacent its by a short vertical bore 45 which is beyond the voutward limit of'travel of the piston 30.

So far asv results are concerned, the exit i bore 44 could open outwardly at any place within the casing box, such for example as straight outwardly or laterally through one of the sides of the c vlinder ridge or lug 37, as will be clear from Fig. 2, the essentialthing` being only that a passageway orbypass is formed around the piston 30, beyond its limits of Ytravel `in each direction of its Amovement. It will be noted that the connecting bores 43, 42, 41, I39, 44 and 1.45, formsuch a bypass or passageway around the piston 30 from within the inner closed end of the cylinder 26 into its open outer end. Y-

Theouter or upper endvof the large vertical bore orV socket 39 is closedv and hermctically -v sealed an inwardly and 'outwardlyl adjustable externally fscrew-threaded tubular valve-carrying plug 46, which -is shown as grooved across; its outer end for the lreception of a screw-driver.

This valve plug 46 i has an inner reduced portion 47 which pro! vides an annular space `withinfthe socketq39 for the flow of the checking fluid and-lat the same timeprovides for-the inward and outward vadjustment koit/this -scr'aw-threaded plug. A bore 48, which is 4shown as of uniform diameter throughout, extends from'end to end centrally through the valveplug 46. A cylindrical valve member 49, havinga conical inner end, is mounted forv sliding fil ' these slots 51 forni stops which limit the sliding movement of the valve member 49 and which, as will presently clearly appear, are of particular utility in limiting the ei:- tent of projection of the conicalinner end of this 4valve member at the inner or downward limit of movement of the latter.

A strong coiled thrust or compression spring 52 is contained in the plug bore 48 with its inner end seated against the outer end of the slidable valve member 49, while its outer end is enga-ged by an inwardly and outwardly adjustable screw-threadedabutment plug 53 which is screwed into' the outer end of this bore 48 and has its outer end provided with a screw-driver groove as shown. The valve spring 52 is normally maintained by the screw plug 53 under a condition of more or less compression or intial tension, so that at all times it will oppose the desiree amount of resilient resistance to the outward sliding movement of the valve member 49 and will normally maintain the conical valve `end of this member at its marimun'i extentl of projection beyond the inner end of the' valve plug extension 47, with the ends of its cross-pin 50 abutting against the stops formed by the lower ends of the ylimiting slots 51.

The valve member 49 constitutes a needle valve for opposing resistance to and thereby flow or passage of the checking fluid in its checking flow under an abnormally high presi sure of this fluid, such abnormallyohighpresnular space is left open between therconical sure being understood to mean a pressure greater than would normally be applied by the door-closing 'spring 18 in the door-clieck ing movement of the piston 30 towards the closed end of the c vflinder26. This valve member 49 is independently adjustable as to each of its above noted functions.

This valve member 49 is normally maintained in a position, as shown in the drawings, in which its conically pointed end extends slightlv into the short bore or aperture 41 which connects and forms the inlet opening from the passage or bore 42 into the lower funnel-shaped wen d of the large vertical bore or socket 39, which lattenas above described, has a free outlet through the exit bore 44. It will be noted that a restricted ansurface of the valve member 49 and the obstantially the usual manner.

tusely angular shoulder which the upper endA of the inlet opening 41 forms with the conically inclined bottoni 40 of the socket 39. According to well understood principles and in a well known manner this restrictedopening impedes the passage of the checking fluid at this point and reduces its rate of flow around the piston 30, through the passage- Away formed by the above described'connected checking fluid within the cylinder iise to an i abnormal maximum extent, the slidable 'valve member 49 will be forced upwardly against the resistance of its spring, thereby to provide a checking opening of larger area which will relieve abnormal pressure and maintain it at a safe maximum, thereby at the same time providing for amore rapid closing movement of the door 8. Thus this single unitary valve device performs effectively the pressure-relieving stiain-pre-- venting operationin accordance with the invention and also at the same time effectively functions in the normal checking operation.

By turning the valve-carrying plug 46 inward or outward the reduced opening past the conical inner end ofthe valve member 49 may be further reduced or enlarged as desired for `thereby regulating or adjusting the checking action to which the door 8 is subjected as it is closed'by the spring 18. In thisoperation it will be noted that the valve member 49 functions as a needle valve in sub- It should be obvious that this adjustment of the valve member 49, by adjusting the valve carrying plug 46, has no effect whatever upon the relief spring 52, since the Valve1ne1nben49, its spring 52 and abutment plug 53 are all mounted in and carried by the valve-adjusting plug 46.

By turning the smaller screw plug 53 inward or outward as may be desired, the normal resistance or initial tension of the relief spring 52 may be increased r decreased, by which it may be made to oppose more or less resistance as desired to the outward or upward sliding pressure-relief movement of the valve member ,49, for thereby affording relief when the strain on the checking mechanismy in its door-closing operation has reached the desired maximum andby reason of such relief, providing also for a more rapid doorelosing movement. -It should be obviousfthat' f this adjustment of the relief spring 52 by means of its adjustable/abutment plug 53 makes no change whatever in the size or area of the restricted checking opening past the inner conical end of tlie valve member 49 and thus has no eect lupon the normal checking operation'. rIlhere is such an interrelation in the general operation, however, that an adjustment of the vsize of the checking openling by means of the larger plug 46 may require a readjustment of the relief spring 52 by means of the abutment plug '53.

It will be Vnoted of the construction shown that it is possible to screw the valve-carrying plug 46 suiiciently inward that the conical end of the valve member 49 will entirely close the checking opening at the upper end of the short vertical bore 41. In such case the normal checking function or operation would of course be lost or eliminated, al-

though the valve device would still continue -to function in substantially the same manner as a pressure relief device, and it is obvious that the valve device shown could be thus l utilized if so desired, although for performing this single function of pressure relief the construction could be Somewhat simplified,

as will hereinafter 4more clearly appear.

Theconstruction o f the valve device shown in Fig. 4 is slightly modiiedand somewhat simpliied-as ycompared with that described with reference to Figs. 1 to 3 inclusive.' Thefeature of adj ustability ofthe pressure relief spring is omitted from the construction shown in Fig. 4, but in other respectsthe construction in general and its manner of operation are substantially the same as in the above described construction shown-'in Figs. 1, 2 and 3, and similar reference numerals have o been applied to corresponding parts. In this particular construction as shown, the outer or upper end portion of the bore or socket 39, for asomewhat modified valve carrying plug 54, is enlarged and screwthreaded to form ashoulder for a sealing gasket 55 which isclamped downOby means of a ring 56 which is screwed into the threaded end portion of this socket, this clamping vring 56 being also internally screw-threaded for receiving thel screw-threaded valve-carrying plug 54, the] screw-threaded portion of which also passes through the gasket 55,

as shown. A 7 t This valve-'carrying plug 54 has at its inner end a reduced shoulder-forming stem portion 57 over the end of which there slidably fits a valve member 58 having a closed conically pointed lower end, this valve member or valve 'tip beingi'n general of cup a0 shape, forming an inverted cap for :the-lower endof the stem 57.-

small pin 59 carried by and passing through the stem 57 lengages at its ends iny vertical slots 60 in theJ sides of the valve member 58. This small pin 59 in cooperation with the slots 60 retains the with the larger screw-threaded plug portion 54. This spring 61 is originally given the desiredpredetermined normal resistance or initial tension for holding the slidable valve member 58 at its innermost or-lowermostposition with the desired force.,

' The remaining parts-of the mechanism of the complete door-closer and check not illustrated in Fig. 4 maybe the same as that hereinbefore described with reference to Figs. f

l, 2 and 3, or could be of some other suitable construction, similarly `in that respect to what is shown in Figs. 1,2 and 3. The operation of this modified construction shown in Fig. 4 is substantially the same as with the valve device shown in Figs. .1, 2 and 3, both in its normal checking operation and in its strain-preventing pressure-relieving opera'- tion. i ing ring 56 might in some instances be dispensed with, and on the other hand if desired they could be utilized in the construc tion shown'in Figs. 1 to 3 inclusive, for'the valve-carrying plug 46,.a'swell as also for the smaller screw plug 53.

Fig. 5 shows a variant or modified form o'f the invention as compared with that shown in Figs. 1 to 3 inclusive. In the construction shown in Fig. 5 the restricting valve or needle valve and the pressure-relief valve are sepa-h rate from each other, but in other respects throughout, the construction may be consideredas the same as that shown in Figs. 1, 2

and 3, and the general manner of operationis substantiallythe same. Overlapping lower and upper longitudinal bores 62 and 63 are provided inthe thickened portion 37 of the Wall of the cylinder 26,l the lower bore 62 communicatin with the inside of the cylinder 26 adjacent to its closed end by means of a short vertical bore 64, while the upper The sealing gasket 55 with its clampbore 63 is shown as opening by means of a vertical -bore 65 into the cylinder near its 'open end outwardly from 'the piston pr 'plunger 30, whichv in Fig. 5 is shown at lts outer or withdrawn position of travel.V

Twoshort vertical bores 66 and 67 extend upwards from the lower horizontal bore 62, of which the bore 67 leads from' the adjacent closed end of this longitudinal bore 62. The

upper end of the bore 66 opens into the conical or funnel-shaped bottom or lower end of a vertical socket bore 68 from which theup` per longitudinal bore 63 leads, while the other short vertical bore 67 opens upwardly into the conical lor funnel-shaped bottom of a similar vertical socket bore 69 which intersects'the upper longitudinal bore 63, so that thereby this upper longitudinal bore 63 communicates with both of the vertical-socket 7'.

bores 68 and 69. Each of the socket bores 68 and 69 extends downward from the outside of the casing box body part l through the cylinder boss 38, and is provided with screw threads in its upper end portion. These two vertical socket bores 68 and 69 are shown as duplicates ofeach other, and each may be substantiallytbe saine as the socket bone 39 shown in Figs. 1, 2 and 3.

Either one of these socket bores 68 and 69 may contain a needle valve for restricting the bore 69, so that by turning this valve plug 71 inward or outward the size of the fluid-restricting opening around the inner conical end of the needle valve 70 may be reduced or enlarged as desired.

The conically inclined bottom of the right hand socket bore 68 forms a valve seat for a valve ball 72 which normally closes the upper end ofthe short vertical bore 66 as shown. This valve ball or valve member 72 is seated by `a strong coiled compression spring 73 locatedabove it in the socket bore 68 and maintained under compression or normal initial tension by means of an abutment plug 7 4 adjustably screw-threaded into the outer or upper end of the socket bore 68. By turning this abutment plug 74 inward or outward the resistance of the spring 73 to upward opening movement of the valve member 72 may be increased or decreased as may be desired, so that thereby there may be obtained the desired relief of abnormal or excessive pressure in the checking fluid together with prevention of undue strain on the checking mechanism. while the door such as 8 may be more rapidly and easily closed. Also the resilient resistance of the relief valve spring 73 to the unseating of the valve ball 72 may be adjusted relatively to the different adjustment of the needlevalve for securing the ,desired cooperatingrelation in operation between the relief valve device and the needle valve.

In the further modified embodiment of the invention shown in Fig. 6, the relief valve device is carried'by the piston 75, the construction in other respects being similar to that shown in Fig. 5'and thegeneral oper# ation being substantially the same as in all of the above described constructions, the ad- ]ustment of the pressurefrelief spring, however, as shown in Fig. 5, being omitted from the construction shown in Fig. 6. In this construction a bore extends entirely through the piston 75, comprising along enlarged outer socket-forming portion 76 and a short inner reduced portion 77 which forms an any nular conical vvalve lseat with the enlarged portion 76 of this bore. `A' ball relief valve 78 is normally held against this seat by a strong coiledcompression spring 79 contained Within the socket 76 and maintained under the desired degree of compression or ini tial tension by a cross-pin 80 which extends across the socket 7 6 adjacent to its outer end and forms an abutment for the outer end of the spring 7 9.

The piston .7 5 diifers from the piston 30 shown in the preceding figures of the draw ings only in the respect that this piston l in the inward or checking movement of. the

piston. This valve ball is prevented from escaping by a small cross pin 84 across the bore 81 and spaced suliicientlyfrom the valve seat to provide ample clearance for the valve ball 88, which is contained loosely in the largev bore 811 t In this construction shown in Fig. 6 the passageway in. the cylinder 26 around the piston 7 5 may be and shown as t'he same as above described with reference to Figs. 1, 2 and 3, and the same reference numerals have 'been applied. The upwardly-opening socket bore 39 contains a needle valve of the same construction as that .described with reference to Fig. 5 and operating in the same way. This needle valve in Fig. 6 similarly comprises an outer :plug adj ustably screwthreaded into the upper end of the socket 39 and carrying at its inner end a reduced needle valve extension' or stem 86, the inner conical end of. which cooperates with the upper end of the short vertical bore 4,1 through the annular coni'cal bottom 4Q of the large bore 39. g.;

In the operation of this construction as .shown in Fig. 6 the checking fluid passes through the connected or interconnnunicating bores in the checking action only, enterlie ing this checking passageway through the f short vertical bore 43 at the closed end of the cylinder 26 and emerging at the open end of the cylinder through the vertical outlet bore 45 beyond the outward limit of travel of the piston 75. In the relief action, under abnormal or excessive pressure of the checking fluid the spring-pressed ball valve member 78 yields away from its seat and provides an additional flow of the checking fluid, which passes through the piston 7 5 from the inner to the outer side thereof.

In Fig. 7 there is shown a slightly variant form of the embodiment of the invention from that shown in Fig. (3 just described, and the parts that remain unchanged have been given the same reference numeral and require no further description. In this construction shown in Fig. 7 a piston or plunger 87 has through it two medium sized bores S8 and 89 of uniform diameter. The inner end of one of these bores, shown as the upper bore 8S, forms a valve seat for the rounded side of a hemispherical valve member 90 which is carried by a straight flat leaf spring 91, the other end of which is secured to the inner end of the piston S7 by means of a screw 92. This leaf spring 91, it will be noted, is thin and weak. so that thereby it does not offer any appreciable resistance to the opening movement of the valve member 90 in the outward or door-opening direction of movement of the piston 87, thus affording a free flow of the checking Huid from the outer to the inner side of the piston S7, while in the i11- ward or checking movement of the piston this spring assists the pressure of the fluid in closing the valve. member 90 against its seat. T his valve member 90 of course corresponds to and operates in substantially the saine way and with substantially the same amountfof freedom of movement as the hereinbefore described valve balls, such as the relief valve ball 35 shown in Fig. 1.

The pressure-relief valve device shown in Fig. 7 operates in substantially the same way as that. described with reference to Fig. (5. As shown in Fig. 7 a. hemispherical valve member 93 seats at its rounded side on the outer eiul of the other bore 89 in the piston S7 and is carried by the end of a leaf spring 91l the other end of which is secured to the outer side of the piston 87 by means of a screw95. It will be noted that this latter leaf spring 9i is rather thick and strong, so that therebyas the piston 87 is moved inward into the cylinder 26 the spring 94 will hold the valve member 93 firmly seated in the normal checking operation. However, abnormal or encessive pressure of th checking fluid during the checking movement ofthe piston, w1ll force the valve member 93 away from its seat against the resistance of its spring 94, thereby permitting the checking fluid to flow away from the closed end of the cylinder QQ through the bore 89 to the other or' outer side of the piston 87.

It is obvious that various modifications may be made inthe constructions shown in the drawings and above particularly described, within the principle and scope of the invention as defined in the appended claims.

I claim:

l. In a door check, a piston, a cylinder in which said piston moves, said cylinder having a by-pass formed therein around the piston, a valve seat in said by-pass, a valve movable toward and from the valve seat and held in adjusted spaced relation to the valve seat to regulate normal flow through said buv-pass, and yie'ldable means. pressing against said valve and permitting abnormal flow of liquid from one end of the cylinder to the other by opeuing'movement of said valve under excessive pressure conditions.

2. In a door check, a piston, a cylinder in which said piston moves, said cylinder having a by-pass formed therein around the piston and having a valve chamber extending laterally from said 1oy-pass and into which respective ends of' the lay-pass opens, a valve lseat at the opening of' one end of the by-pass into the chamber, a valve supporting member screwed into the end of the chamber remote from the valve seat to move toward and from said seat, a valve carried by said member to move therewith toward the valve seat, said valve being normally spaced from said seat, a spring urging the valve away from`said member toward said seat, and means to limit movement of the valve away from said member. f

3. In a door check, a piston, a cylinder in which said piston moves, said cylinder having a by-pass formed therein around the piston and having a valve chamber extending laterally from said by-pass and into which the lay-pass opens, a valve seat at the opening of' the by-pass into the chamber, a valve supporting member screwed into the end of the chamber remote from the valve seat to move toward and from said seat, a valve carried by' FORREST C. GARRISON.

llll

liu 

